JPH0661298B2 - rice cooker - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to temperature control of a rice cooker, and in particular, when the temperature of the rice cooker cannot accurately detect the temperature of the rice cooker due to poor contact with the rice cooker. The present invention relates to a rice cooker designed to prevent rice cooking.

[Conventional technology]

A conventional rice cooker will be described with reference to FIG. 6, FIG. 7 (A), (B), and FIG. In the figure, (1) is a rice cooker body, (2) is a pot that is detachably installed in the rice cooker body, and (3) is a bottom part of the rice cooker body (1). ) Is a heating means for heating the outer bottom of the rice cooker, and (4) is a sensor (4) provided at the center of the inner bottom of the rice cooker body (1) and urged to contact with the center of the outer bottom of the pot (2). Temperature detection means having 4a),
(5) is rice stored in the kettle (2), (6) is counting means for counting a predetermined temperature of the temperature detected by the temperature detecting means (4), and (7) is counting means (6) Cooked rice amount detecting means for receiving the input and detecting the cooked rice amount, (8) is this cooked rice amount detecting means (7)
And heating amount control means for controlling the heating means (3) by receiving an input from the temperature detecting means (4).

Next, the operation will be described. First, attach the pot (2) to the rice cooker body (1).
Take it out, and put the desired amount of polished rice (5) and an appropriate amount of water in the kettle (2). Then, store it again in the rice cooker body (1). As described above, when rice cooking is started after the completion of setting, the rice cooking heater (3) generates heat and heats the pot (2). When the kettle (2) is heated, the temperature of the rice (5) also rises following it.
At this time, the temperature of the kettle (2) is constantly detected by the temperature detecting means (4) having the sensor (4a), and the counting means (6) counts a predetermined temperature of the detected temperature, and the count result is obtained. The amount of cooked rice detecting means (7) is input to detect the amount of cooked rice. The heating amount control means (8) receives inputs from the temperature detecting means (4) and the rice cooking amount detecting means (7) to control the rice cooking heater (3).

When the kettle (2) is heated and the temperature reaches around 100 ° C, rice (5) begins to be cooked. The temperature of the kettle (2) maintains an almost constant value as the water boils, but when the water in the kettle (2) runs out, the temperature of the kettle (2) rises sharply and is set according to the amount of cooked rice. Completed cooking temperature (for example, 11 when cooking a small amount of rice)
The heating amount control means (8) cuts off the power supply to the heating means (3) when the temperature reaches 5 ° C. or 123 ° C. when a large amount of rice is cooked. As described above, the heating amount control means (8) receives an input from the cooking amount detection means (7) for detecting the cooking amount in the pot (2) during the cooking process, so that the cooking completion temperature can be selected. Is. Then, after the power to the rice cooking heater (3) is cut off,
Move to the steaming process.

FIG. 7 (A) is a temperature characteristic diagram when a small amount of rice is cooked, Ts-a
Indicates the temperature detected by the temperature detecting means (4), and Tr-a indicates the temperature of the rice (5) in the kettle (2). Since the energization is cut off, it can be seen that the temperature of Ts-a gradually decreases.

FIG. 7 (B) is a temperature characteristic diagram when cooking a large amount of rice, Ts-b
Is the temperature detected by the temperature detecting means (4), and Tr-b is the temperature of the rice (5). Because it is a large amount of rice, 100 more than when cooking a small amount
It can be seen that it takes a long time to reach around ℃. The counting means (6) counts this difference in length. In addition, the cooking is completed at 123 ° C and the heating means
Since the power supply to (3) is cut off, it can be seen that the temperature of Ts-b gradually drops.

[Problems to be Solved by the Invention]

In the conventional rice cooker, the rice cook temperature characteristic is created by the above control when the rice is cooked when the contact between the kettle (2) and the sensor (4a) is normal. For example, as shown in FIG. When foreign matter such as rice (5) is caught between the outer bottom surface and the sensor (4a), the sensor (4a) cannot accurately detect the temperature of the pot (2) and the rice cooker It will be in the form of detecting the heat rise of (3). FIGS. 7 (C) and (D) are temperature characteristic diagrams in that state. When the detection temperature of the sensor (4a) rises sharply and the rice cooking amount detecting means (7) detects that the rice is a small amount, The electricity to the rice cooking heater (3) is cut off at 115 ° C, and when it is detected that a large amount of rice has been cooked, it is cut off at 123 ° C. Since the input of the rice cooking amount detecting means (7) is the temperature detecting means (4), the detection is completely unreliable, so even if the amount is large, the electricity to the rice cooking heater (3) is cut off at 115 ° C. It can happen.

Moreover, since the temperature detecting means (4) is configured to detect the temperature of the rice cooking heater (3), there is no longer a condition where the detected temperature becomes constant like the normal contact state until the rice cooking completion temperature is reached. As shown in medium Ts-c and Ts-d, the rice cooking temperature is reached faster than normal, and the power to the rice cooking heater (3) is cut off. As a result, the temperature of rice (5) in the pot (2) is
As shown in −c and Tr−d, the slope of the rising curve is gentle and even when the temperature detecting means (4) reaches the rice cooking completion temperature,
Since the temperature was still low, the rice (4) could not be cooked, but it moved to the steaming process as it was, and there was the problem that so-called raw cooked rice could be made.

Further, as shown in FIGS. 9 to 11, Japanese Patent Laid-Open No. 62-26036.
In Japanese Patent Laid-Open Publication No. 2003-242242, it relates to poor contact between the hot plate type rice cooking heater (3) and the pot (2).
Since (4) detects the temperature of the cooker (2) while being affected by abnormal heating due to poor heat conduction of the rice cooking heater (3), the temperature rise curve peculiar to rice cooking is detected. Therefore, in the normal contact state, as shown in FIG. 10, the temperature range from 110 ° C. to 120 ° C. corresponds to the dry-up time, whereas in the abnormal contact state, the temperature rises during boiling as shown in FIG. Depending on the time difference, the cooking completion temperature may be 12
The choice was 0 degrees or 135 degrees. However, this control does not deal with the sudden rise in the detected temperature caused by the contact abnormality between the shuttle (2) and the sensor (4a).

The present invention has been made to solve the above problems, and an object thereof is to obtain a rice cooker capable of preventing raw cooked rice caused by abnormal contact between the pot and the temperature detecting means.

[Means for Solving the Problems]

Rice cooker body, a pot that is detachably housed in the rice cooker body and stores rice, a heating means for heating rice through the pot, a first temperature that is in contact with the pot and is set near the boiling temperature Between the first temperature and the second temperature set in a temperature range higher than the first temperature and lower than the rice cooking completion temperature, the first elapsed time between the first temperatures and the second temperature. Measuring means for measuring the second elapsed time between the temperatures, abnormality detecting means for comparing the first elapsed time with the second elapsed time to detect an abnormality in the cooked rice state, and the abnormality detecting means for detecting the abnormality. In this case, after the heating of the rice is stopped for a certain time, the heating amount control means for controlling the heating means so as to heat the rice to a predetermined temperature higher than the rice cooking completion temperature is provided.

[Action]

In the present invention, the temperature detection state detection control means detects an abnormality in the contact state between the temperature detection means and the kettle and controls the heating amount control means.

Example of Invention

An embodiment of the present invention will be described below with reference to FIGS.

In the figure, (1) to (8) are almost the same as the conventional rice cooker. Reference numeral (9) is an arithmetic means for receiving an input from the counting means (6), applying an equation to be described later to perform an arithmetic operation, and transmitting an output to the heating amount control means (8) based on the arithmetic result. The temperature detecting means (4), the counting means (6), the rice cooking amount detecting means (7), the heating amount controlling means (8) and the calculating means (9) are detected from the memory storing the processing program and the sensor (4a). A circuit for inputting a signal and a signal from a switch (not shown), an output signal obtained by a program process based on the signal input to this input circuit, that is, a heating amount control signal, via the output circuit. It is composed of a microcomputer equipped with a CPU for outputting to 3).

The counting means (6) and the computing means (9) are collectively referred to as a temperature detection state detection control means (10). Next, regarding the operation, the second
It will be described with reference to FIGS. In the figure, T ₁ is a cooking temperature of 115 ° C. when cooking a small amount of rice, T ₂ is a cooking temperature of 123 ° C. when cooking a large amount of rice, T ₃ is 95 ° C., T ₄ is 110 ° C., and T ₅ is 11
2 ° C and T ₆ are set at 120 ° C. Counting means
(6) selectively counts between these temperatures according to the detection result of the cooked rice amount detecting means (7). That is, when a small amount is detected, the temperature is between T _{3 and} T ₄ (referred to as τ ₁ ) and T _{5 to} T _1.
The temperature interval (referred to as τ ₂ ) is counted, and when detected as a large amount, τ ₁ and the T ₆ -T ₂ temperature interval (referred to as τ ₃ ) are counted. Then, the calculation result is input to the calculating means (9) and is applied to the following formula to determine whether the rice is normally cooked or abnormally cooked.

τ ₁ / τ ₂ ≧ Y ...... (Small amount normal) τ ₁ / τ ₂ <Y …… (Small amount abnormal) τ ₁ / τ ₃ ≧ Y …… (Large amount normal) τ ₁ / τ ₃ <Y …… (Large amount) Abnormal) ~ There are formulas, but the formula is for small amount rice cooking, and the formula is for abnormal rice cooking. The value of Y is set to 6 in advance, and if τ ₁ / τ ₂ or ₁ / τ ₃ is 6 or more, it is determined as normal rice cooking, and if less than 6, it is determined as abnormal rice cooking.

As described above, the calculation means (9) outputs the heating amount control means (8) based on the calculation result so that the rice cooks normally when the rice is cooked and then shifts to the unevenness stage after completion of cooking. After the lapse of time (Th), the rice heating heater (3) is heated with low heat until the temperature detecting means (4) detects 133 ° C. ”The heating amount controlling means (8) is output to perform the raw rice cooking step. It is a thing. As a result, the rice will stay at 100 ° C for about 15 minutes or longer.
Can be maintained and alpha conversion is promoted. First of all, the pot
A case where a small amount of rice is cooked while the contact between (2) and the sensor (4a) is normal will be described. The temperature characteristic diagram at this time is shown in FIG. 3 (A), and Ts-e is the temperature detecting means (4).
The detection temperature of Tr-e is the rice (5) temperature. After the start of rice cooking, the counting means (6) counts between the predetermined temperatures detected by the temperature detecting means (4) as in the conventional case,
The rice cooking amount detection means (7) inputs this count result and detects the rice cooking amount (step 11). Next, temperature detection means (4)
When the T ₃ temperature is detected (step 12), the counting means (6) starts counting. (Step 13) Next, when the temperature detecting means (4) detects the T ₄ temperature (Step 1)
4) The counting means (6) stops counting (step 15). As a result, τ ₁ is counted. Next, on the basis of the result detected by the rice cooking amount detecting means (7) (step 16), if small amount of rice is cooked, it moves to step 17, and if large amount of rice is cooked, it moves to step 22. In this case, since the amount is small, the process proceeds to step 16. When the temperature detecting means (4) detects a T ₅ temperature in step 17, counting means (6) starts counting again (step 18). When the temperature detecting means (4) detects the T ₁ temperature (step 19),
The counting means (6) stops counting (step 2
0). As a result, τ ₂ is counted.

Next, the calculating means (9) inputs τ ₁ and τ ₂ counted by the counting means (6). It is assumed that τ ₁ at this time is counted as 12 minutes and τ ₂ is counted as 1 minute. The calculation means (9) applies this numerical value to the following formula to perform calculation (step 21).

(τ ₁ ) 12 / (τ ₂ ) 1> (Y) 6. Here, the reason why τ ₁ is as long as 12 minutes will be explained.

When rice is cooked in a normal contact state, the time for the temperature detecting means (4) to continuously detect a constant temperature during τ ₁ (when the water in the kettle (2) is in a boiling state) is incorporated. As shown in FIG. 3 (A), it becomes very long with respect to τ ₂ . On the contrary, τ ₂ is as short as 1 minute because the water in the kettle (2) is exhausted and the temperature of the kettle (2) rises rapidly. Next, in step 27, the calculation means (9) determines that the rice is normally cooked based on the calculation result. After the completion of cooking, the process proceeds to step 28 to perform a muffler stroke, and then the cooking of rice is completed. Next, a case where a large amount of rice is cooked in a state where the contact between the pot (2) and the sensor (4a) is normal will be described.
The temperature characteristic diagram at this time is shown in FIG. 4 (A), Ts-g is the temperature detected by the temperature detecting means (4), and Tr-g is the temperature of the rice (5). The description of steps 11 to 15 is omitted since it is substantially the same as the case of performing the small amount rice cooking. Step 1
Based on the result detected in step 11 in step 6, the process moves to step 22, and when the temperature detecting means (4) detects the T ₆ temperature, the counting means (6) starts counting (step 23). Next, when the temperature detecting means (4) detects the T ₂ temperature (step 24), the counting means (6) stops counting (step 25). As a result, τ ₃ is counted. At this time, τ ₁ is 4 minutes and τ ₃ is 0.5 minutes. When this is calculated in step 26, (τ ₁ ) 4 / (τ ₃ ) 0.5
When ≧ Y (6), the calculation means (9) determines that the rice is normally cooked in step 27, and after the cooking is completed, the process is transferred to step 28, and the rice is finished after performing the unevenness stroke.

The reason why τ ₂ is counted when a small amount of rice is cooked and τ ₃ is counted when a large amount of rice is cooked will be described with reference to FIGS. 4 (A) and 5.

Ts-h shown in FIG. 5 is a characteristic curve of the temperature detected by the temperature detecting means (4) when a small amount of rice is cooked in the normal contact state, and Ts-j is a temperature when a large amount of rice is cooked in the normal contact state. It is a characteristic curve of the temperature detected by the detection means (4). As can be seen in the figure, the temperature at which the measured temperature is constant and the temperature at the dry up are different. Therefore, when τ ₂ is counted when cooking a large amount of rice, the time when the detected temperature becomes constant is counted as shown in FIG. 4 (A), and it becomes longer than τ ₁ . The calculation means (9) inputs this,
When the calculation is performed by using the above formula, an abnormal contact state may be detected despite the normal contact state. Therefore, when cooking a large amount of rice, the temperature range between T ₆ and T ₂ (τ ₃ ) is higher than the temperature range between T ₅ and T ₁ (τ ₂ ).
Is counted to prevent the above false detections from occurring.

Next, the case where the shuttle (2) and the sensor (4a) are in abnormal contact will be described.

Although the amount of cooked rice is judged at step 11 after the start of cooking rice, it is impossible to make a correct judgment because the pot (2) and the sensor (4a) are in abnormal contact. For example, even if a large amount of rice is cooked, it may be determined that it is a small amount of rice. Therefore, here, not a case where a large amount or a small amount of rice is actually cooked is explained, but a case where the rice cooking amount judging means (7) judges a large amount or a small amount will be explained. The reason for explaining in this way is that the abnormal rice cooking can be determined and the corresponding rice cooking control can be performed without knowing the rice cooking amount at all. The step will be described below.

First, the case where the rice cooking amount determination means (7) determines in step 11 that the amount is small is described. FIG. 3 (B) is a temperature characteristic diagram at this time, Ts-f is the temperature detected by the temperature detecting means (4),
Tr-f is the temperature of rice (5).

From step 12 to step 15, τ ₁ is counted after the same progress as in the small amount rice cooking in the normal state. Next, in step 16, the process proceeds to step 17 based on the result of step 11. Until step 17 to step 20 ₂ tau passed in the same manner as in the minor cooking during the normal is counted.

At this time, τ ₁ is 4 minutes and τ ₂ is 1 minute. When this is calculated in step 21, (τ ₁ ) 4 / (τ ₂ ) 1 <(Y) 6. Then, it is judged to be abnormal in step 27, the process proceeds to step 29, and after the cooking is completed, the rice cooking heater (3) is heated with low heat until the temperature detecting means (4) detects 133 ° C. after the holding time (Th) has elapsed. The process shifts to the raw-cooking and rice-cooking process, and then the mulling process is performed to complete the rice-cooking.

Here, the reason why the time difference between τ ₁ and τ ₂ is not so large will be described.

As can be seen from the characteristic curve of Ts-f in FIG. 3 (B),
The temperature is rising almost constantly. This is the sensor (4a)
This is because the temperature of the rice cooking heater (3) is wider than the temperature of (2). Therefore, the constant temperature time and the dry-up time are not included in τ ₁ and τ ₂ , and the time difference is reduced.

Next, a case where a large amount of rice is cooked while the kettle (2) and the sensor (4a) are in abnormal contact will be described. The temperature characteristic diagram at this time is shown in FIG. 4 (B), where Ts-L is the temperature detected by the temperature detecting means (4) and Tr-L is the temperature of rice (5). As described above, the temperature detecting means (4) detects a constant temperature rise. Therefore, τ _{3 which} is counted when a large amount of rice is detected is counted τ when it is detected as a small amount of rice.
_It can be said that the time is almost the same as ₂ .

As a result, τ ₁ / τ ₃ <Y is detected and abnormal rice is detected, and as mentioned above, rice is completed after shifting to the raw rice cooking process.

As described above, the rice (5) is caught between the kettle (2) and the sensor (4a), and the temperature of the kettle (2) cannot be detected correctly. Even when the rice is cooked raw, the cooked rice is cooked. Rice based on process (5)
Since it is cooked, you can prevent raw cooking.

Although the amount of cooked rice is detected in step 11 in the above embodiment, the amount of cooked rice may be detected by the counting length of τ ₁ .

In the above embodiment, the normal contact and the abnormal contact are detected by the ratio of τ ₁ and ₂ and τ ₃ , but they may be detected by the quickness of the arrival time to the cooking completion temperature. The method is not limited to this.

In addition, since the holding time (Th) is provided in the above-described embodiment, the sensor (4a) can be cooled during that time, and the temperature is raised by a low heat thereafter, so that the time to reach the rice cooking completion temperature 133 degrees should be longer. Can be done. During this time, the temperature of the rice in the kettle (2) is around 98 ° C, and this state is for 20 minutes ~
It is described in "Cooking and Rice" published by Gakken Shoin Co., Ltd. on August 1, 1979 that it is indispensable to keep starch for 30 minutes from the β state to the α state. .
Further, in the above embodiment, by providing the hold time (Th),
I tried to keep the rice temperature around 98 degrees for a long time, but 133
The control may be performed so that the time to reach the predetermined time is the predetermined time, and the control method is not limited to this.

Further, a notification means such as a buzzer chime or a lamp may be provided to notify the user of the abnormality when the abnormality is detected in step 27.

〔The invention's effect〕

As described above, according to the present invention, the passage between the first temperature set near the boiling temperature and the second temperature set within the temperature range higher than the first temperature and lower than the rice cooking completion temperature. Times are measured and compared, and the comparison value is used to detect an abnormality in the cooked rice state. Therefore, there is an effect that it is possible to reliably prevent raw rice from being cooked.

[Brief description of drawings]

Fig. 1 is a functional block diagram of the present invention, Fig. 2 is a flow chart, Fig. 3 (A) is a temperature characteristic diagram of a small amount of rice cooked during normal contact rice cooking, and Fig. 3 (B) is an abnormal contact rice cooked rice. Temperature characteristics of small amount of rice, Fig. 4 (A) is temperature characteristics of large amount of rice when normal contact rice is cooked, Fig. 4 (B) is temperature characteristics of large amount of rice when abnormal contact rice is cooked, and Fig. 5 is small amount. Explanatory diagram showing the difference in temperature characteristics between cooked rice and large quantity cooked rice, FIG. 6 is a functional block diagram of a conventional rice cooker, FIG. 7 (A) is a temperature characteristic chart of small quantity cooked rice during normal contact cooked rice, 7th Figure (B) is a temperature characteristic diagram of large amount of rice cooked during normal contact rice cooking, Figure 7 (C) is a temperature characteristic diagram of small amount of rice cooked during abnormal contact rice cooking, and Figure 7 (D) is a large amount rice cooked under abnormal contact rice cooking. FIG. 8 is a temperature characteristic diagram, and FIG. 8 is an explanatory view of the state of the pot and the sensor at the time of abnormal contact rice cooking. FIG. 9 is a block diagram of another conventional rice cooker, FIG.
The figure shows the temperature characteristics of the sensor during normal rice cooking, and Fig. 11 shows the temperature characteristics of the sensor during abnormal rice cooking. In the figure, (1) is a rice cooker body, (2) is a pot, (3) is heating means, (4) is temperature detecting means, (5) is rice, (7) is rice amount detecting means, and (8) is The heating amount control means (10) is a temperature detection state detection control means. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masakazu Kobayashi 1728 Omaeda, Omaeda, Hanazono-cho, Ozato-gun, Saitama 1 Mitsubishi Electric Home Equipment Co., Ltd. (56) Reference JP-A-63-252112 (JP, A)

Claims (1)

[Claims] 1. A rice cooker main body, a kettle that is detachably accommodated in the rice cooker main body and stores rice, a heating means for heating rice through the kettle, and the heating means is in contact with the rice cooker and set to a temperature near the boiling temperature. Between the first temperature and the second temperature set in a temperature range higher than the first temperature and lower than the rice cooking completion temperature, respectively, the first temperature between the first temperature Measuring means for measuring the second elapsed time between the elapsed time and the second temperature, abnormality detecting means for comparing the first elapsed time with the second elapsed time to detect an abnormality in the cooked rice state, the abnormality detection When an abnormality is detected by the means, after heating the rice for a certain period of time is stopped, a heating amount control means for controlling the heating means so as to heat to a predetermined temperature higher than the rice cooking completion temperature is provided. Rice cooker.